Lubrication of a marine propulsion device



July 3, 1962 W. J. SHIMANCKAS LUBRICATION OF' A MARINE PROPULSION DEVICEFiled Nov. 2l, 1960 M4, mslm 3,042,146 LUBRICATION F A MARINE PROPULSIUNDEVICE William .'l. Shimanclras, Waukegan, lll., assigner to OutboardMarine Corporation, Waukegan, Ill., a corporation of Delaware Filed Nov.21, 1960, Ser. No. 76,773 l0 Claims. (Cl. 184--6) This invention relatesto lubrication of a marine propulsion device. The invention hasparticular application to lubrication of the drive gears of an outboardmotor or an inboard-outboard driving arrangement.

There are advantages in using the submersible housing parts of a marinepropulsion device for the storage of oil required for lubrication. Inthe first place, considerable storage space is available and in thesecond place the oil thus stored is cooled by release of its heat to thewater in which the device operates.

However, it is found that if gearing which transmits motion from thedrive shaft to the propeller shaft is required to operate fullysubmerged in oil, there is a very considerable loss of power. Themeshing gear teeth compress and circulate the oil within the housing. Asubstantial part of the available power may be consumed in this mannerwithout contributing to the propulsive effort.

All of the advantages of oil storage in the lower unit can be retained,and the power loss is greatly reduced, by withdrawing from the gearcasing all of the oil not actually required for the lubrication of thegears, such oil being maintained in circulation during the operation ofthe device by the provision of an elevated oil-receiving chamber whichhas restricted communication with the gear case through a metering oricehaving a capacity less than that of the withdrawal pump. Thus, shortlyafter the device is put into operation, the excess pump capacity willremove all excess oil from the gear case and will continue to remove theoil which is constantly in circulation, trickling back into the gearcase.

Obviously, the circulating oil can be used for lubricating otherportions of the marine propulsion device and this is exemplified in anin-board-outboard organization in which there are gears at an upperlevel to which the oil is supplied before it passes to the elevatedstorage chamber from which it trickles back to the submerged gear casein the course of its recirculation.

In the drawings:

FIG. l is a fragmentary detail view in longitudinal vertical sectionthrough a portion of the lower unit of an outboard motor embodying theinvention.

FIG. 2 is a similar view on a reduced scale diagrammatically showing inlongitudinal vertical section a portion of the vertical strut of aninboard-outboard organization embodying the invention.

In the shaft housing or vertical strut portion 5 of the lower unit of anoutboard motor as fragmentanily illustrated in FlG. l, there isunitarily included a gear case chamber 6 in which the propeller shaft 7is provided with bearings at 8 and 9 for the driving of propeller 10.

A vertical drive shaft i1 powered by an engine (not shown) is piloted inthe hub 12 of the driving pinion 13 which meshes with gears 14 and 15.These gears are free on the propeller shaft 7 except as coupled theretoby the shiftable clutch collar 16, which may be moved through theneutral position illustrated into engagement with either gear 14 or l5by means of a shipping lever 17 actuated by rod 18.

A partit-ion 19 separates the gear case portion 6 of the apparatus froman elevated oil reservoir at 20. In the generic aspect of the invention,and looking only at the problem of removing the oil from the gear case,the

- smarte ig@ Patented July 3s 1962 reservoir 20 might be separate and atany convenient location. There are, however, advantages in placing it inthe lower unit as shown. In any event, limited communication permittingthe oil to trickle back into the gear case is provided. In the preferredembodiment, this is accomplished in a metering oriiice 2.1 in partition19. When the parts are at rest, the oil will stand approximately at thelevel indicated at 22 in FIG. 1.

When the drive shaft 11 is in operation, both the gears 14 and 1S arecontinuously actuated. Under these conditions, the cam 23 on the hub ofdriven gear 14 engages a cam follower 24 on the pump plunger 25 todisplace the plunger downwardly against the bias of spring 26. The oilreceived into the cylinder 27 through the intake port 28 will be forcedby downward movement of the pump plunger 25 to pass through the port 2Sinto the reservoir Ztl, ultimately iilling such reservoir to the levelillustratively suggested at Sti. The location of the pump intake port 28will determine the level 31 at which oil will be maintained in gear case6, the desired arrangement being such that the peripheries of the gears14 and l5 dip into the oil without undue displacement thereof.

No valve is necessary because the resistance of the duct 2.9 issudiciently high so that there is little backward flow of the oil in theupstroke of the plunger 25 under bias of spring 26. Any partial vacuumcreated in the cylinder Z7 is relieved when the piston clears the intakeport 2S. The positive pressure of the plunger in response to the actionof cam 25 is suiiicient to force the oil through duct 29 notwithstandingthe flow resistance offered by the duct.

Even at the elevated level 30 4to which the oil is raised in thereservoir 2liduring pump operation, most or all of the oil is belowwater level, the water level being apu proximately the same as the oillevel 30 during normal use of the device. Thus all of the recirculatingoil is cooled. However, even if the water level were materially lowerthan contemplated, the oil would still be cooled by circulating throughthe gear housing, there being a constant trickle of oil owing by gravityfrom the chamber 20 to the gear housing through the metering orifice 2l,which regulates the rate of such flow to an amount which is less Vthanthe oil displaced by the pump 2S. Because of the difference `between theamount of oil pumped and that returning through the metering orifice,the oil in the gear housing 6 is kept at the minimum level required forlubrication of the gears.

Pressure is desirably equalized or at least balanced between the gearhousing and the oil storage chamber 20. This may conveniently be done byproviding a port at 32 above oil level in the reservoir 20, the portopening into the passage 33 in which the rod 18 is disposed. Since thispassage is in open communication with the gear case 6, there will be noback pressure which could preclude movement of the oil in eitherdirection.

In actual practice some sort of water pumping arrangement will be usedto cool the ,engine (not shown) which powers the drive shaft 11. Avariety of Water pumps are known to the art and since the water pumpforms no part of the present invention, it is not illustrated in FIG. l.However, one optional arrangement for pumping water is illustratedincidentally in FIG. 2 and a similar structure may be used in theyoutboard motor or propulsion unit device pictured in FIG. l.

The organization shown in FIG, 2 comprises a Vertical strut portion ofan inboard-outboard marine propulsion device. The strut portion Si)l istiltably mounted on means not shown to pivot about a transversehorizontal -axis designated at 34. This axis is on the pitch circle of apair of gearlike coupling elements 35, 36 which function as a universaljoint to accommodate pivotal movement of the strut 50 while maintainingdriving connection 'oetween the power shaft 37 and the extension shaft38 which mounts the gear 39. This gear meshes within the gear 40 at theupper end of the vertical drive shaft 11) which corresponds to thevertical drive shaft 11 in the FIG. l embodiment. The housing 45comprises a gear case chamber which encloses the gears 39 and 40 toretain lubricant therefor. The lubricant is maintained at a levelindicated at 46 by the overflow duct 47 which communicates through ahose 48 with another duct 49 leading to the lubricant storage chamber200. From the reservoir Zilli), the oil trickles through a meteringoriiice 21() into the gear casing 6d in which the pinion 130 and thedriven gears i4!) and 150 are disposed. In the diagrammatic showing, thereversing clutch is omitted but it will be understood that anarrangement similar to that of FIG. 1 will ordinarily be employed tocouple the gears 140 and 150 selectively to the shaft 70 upon whichpropeller 100 is mounted.

The cam 30, which is here shown on the hub of gear 150, drives the pumpplunger 256 to pump oil from the gear casing when the parts are inoperation. The pump cylinder 270` has its inlet at 286 and contains aspring 260 which biases the pump plunger 250 upwardly.

Oil displaced by the pump plunger d is discharged through the duct 2d.An annular groove 52` extends around the propeller shaft bearing Sti andcommunicates with ducts 53, S4, 55 leading to the -top of the strut anddischarging at 56 into the upper gear case 45. The level of the overiiowduct 47 will determine Athe level of oil maintained in this gear casefor the lubrication of the gears 39 and 4G, as the overow is returnedthrough duct 49 to the reservoir 200;

Thus, `circulation is maintained throughout both gear cases and thereservoir without maintaining in either gear case during operation anoil level higher than is required for actual lubrication of the gears.

In this embodiment, pressures in the several chambers may convenientlybe balanced by `making the shaft 110 tubular. The internal shaft duct111 opens through gear di) into the upper gear case 45 and through gear130 into the lower gear case 60. A drilled hole at 112 places duct M1 incommunication with reservoir 200. In this embodiment, the duct 111communicates with air space above operating oil levels in all threechambers to equalize pressures throughout during operation and tobalance pressures when the lower gear case is full of oil with the partsat rest.

With the parts at rest, much of the oil in the reservoir will flowthrough the metering orifice 210 into the lower gear case, but as soonas drive shaft 110 is in motion, the surplus oil will be pumped from thelower gear case to the upper gear case and thence will iiow to thereservoir to maintain the oil in the reservoir at `the elevated levelshown.

I claim:

1. In a mar-ine propulsion device having a submersible gear case and anoil storage reservoir at a higher level and power-operated gears andshafts in said gear case, means for pumping from said gear case to saidreservoir surplus oil beyond that required for the lubrication of saidgearing, said pumping means Ihaving an oil inlet so located as to definea working level of oil in said gear case well Abelow the top thereof,means for driving the pumping means from one of said shafts whenever theshafts and gearing are in operation, and means providing a restrictedmetering communication between the reservoir and gear case having flowcapacity less than that of said pumping means for the gravity iiow ofoil from the reservoir to the gear case at a rate less than the rate atwhich the pumping means removes oil from the gear casing, whereby tomaintain continued circulation of oil between the reservoir and the gearcasing during shaft-and gear operation while keeping surplus oil drainedfrom the gear casing.

2. The device of claim 1 in which the propulsion device comprises anupright strut member having a generally upright drive shaft and agenerally horizontal propeller shaft, the gearing including gears on thedrive shaft and propeller shaft in mesh for providing connection betweensaid shafts, the oil level being materially below the level at whichsaid gears mesh, and said gear casing and the strut member having aninterior partition subdividing it to separate said gear casing from acavity above the casing constituting said reservoir, said partitionhaving an opening constituting said metering orifice, and a separatemeans communicating with the reservoir and the gear case for balancingpressures there- 1n.

3. In a marine propulsion device having a submersible gear case and anoil storage reservoir at a higher level and power-operated gears andshafts in said gear case, means for pumping from said gear case to saidreservoir surplus oil beyond that required for the lubrication of saidgearing, said pumping means having an oil inlet so located as to defineya working level of oil 4in said gear case, means for driving thepumping means from one of said shafts whenever the shafts and gearingare in operation, and means providing a restricted meteringcommunication between the reservoir and gear case having flow capacityless than that of said pumping means for the gravity flow of oil fromthe reservoir to the gear case at a rate less than the rate at which thepumping means removes oil from the gear casing, whereby to maintaincontinued circulation of oil between the reservoir and the gear casingduring shaft and gear operation While keeping surplus oil drained fromthe gear casing, the propulsion unit comprising an upper gear casehaving Agearing therein requiring lubrication, said pumping means havinga discharge connection leading to said upper gear case and said uppergear case having an over-ow port leading `to said reservoir for thestorage in the reservoir of oil pumped from the rst mentioned gear caseto t-he upper gear case during the operation of the gears and shafts inthe lower gear case, such oil Abeing in continuous circulation duringsuch operation, while being maintained during operation at a level inthe lower gear case which is materially below the top of said lower gearcase.

4. The device of claim 3 in which duct means is provided for placingboth gear casings and the reservoir in communication independently ofpump and port.

5. The device of claim 3 in which one of said shafts extends from theupper gear case to the gear case rst mentioned, the shaft being tubularand having an internal duct communicating with both gear cases and alateral port opening into the reservoir and providing pressure balancingcommunications between the gear cases and reservoir.

6. In a marine propulsion unit, a strut element interiorly provided withan oil storage reservoir and having at its lower end a submersible gearcase, a propeller shaft and at least one continuously dri-ven gear insaid gear case, a drive shaft extending through said strut and providedwith a pinion meshing vwith said gear, a pump having an oil pumping partoperatively provided with means for driving it from one of said shafts,said pump comprising a chamber having an inlet opening from said gearcase at a level below the level of mesh of said pinion and said gear anddeterminative of a desirable level of oil in said gear case well belowthe top thereof, means providing a pump discharge conduit leading fromsaid pump to a level above the -gear case and having a dischargeconnection to said reservoir, said reservoir having a metering portproviding gravity communication between the reservoir and gear case,said port having an oil ilow capacity less than the pump-producedcapacity of said conduit.

7. In a marine propulsion unit, a strut element interiorly provided withan oil storage reservoir and having at its lower end a submersible gearcase, a propeller shaft and at least one continuously driven gear insaid gear case, a drive shaft extending through said strut and providedwith a pinion meshing -with said gear, a pump having an oil pumping partoperatively provided with means for driving it from one of said shafts,said pump comprising a chamber having an inlet from said gear case at alevel determinative of a desirable level of oil in said gear case, meansproviding a pump discharge conduit leading from said pump to a levelabove the gear case and having a discharge connection to said reservoir,said reservoir having a metering port providing gravity communicationbetween the reservoir and gear case, said port having an oil flowcapacity less than the pump-produced capacity of said conduit, the pumpinlet port being disposed at a level intersected by a lower peripheralpart of said gear, the pump comprising a displacement plunger having anupward biasing spring, and having a cam follower, said gear having acam-shaped hub portion acting on the follower opposite to the action ofsaid spring on the follower to displace the plunger in opposition tosaid spring.

8. A marine propulsion device comprising a generally upright housingwith partition means defining a gear case near Ithe bottom of thehousing, a reservoir at an intermediate level in the housing, and anupper gear case near the upper end of the housing; conduit meansextending from the upper gear case to the reservoir; the partition meansbeing provided with a metering port between the reservoir and the firstmentioned gear case at the lower end of the housing; a drive shafthaving portions in both gear cases; a propeller shaft in the gear caseat the lower end of the housing; said drive shaft and propeller shafthaving meshing gears; a power shaft; meshing gears on the power shaftand the drive shaft and disposed in the gear case at the upper end ofthe housing; a pump means having an inlet from the gear case at thelower end of the housing at a level approximating the lower peripheralportions of said propeller shaft gear, said pump means having an oildisplacement capacity in excess of the gravity flow capacity of the portand having connections for delivering oil from said inlet to the gearcase at the upper end of the housing, said last mentioned gear casehaving an overflow duct at a level just adequate for the lubrication ofthe gears therein and leading via the conduit means to said reservo1r.

9. In a marine 4propulsion device having a propulsion unit which issubmerged during normal operation and which contains a propeller shaft,a gear thereon, a driving gear meshing with the propeller shaft gear ata level above the propeller shaft, and a gear case in which said gearsare conned, the combination therewith of means for powering the drivinggear and including parts remote from said gear case and requiringlubrication, means within said propulsion unit providing an oilreservoir, said means including a partition having a metering portconnection for gravity lW of oil from the reservoir to the gear caseaforesaid, and pump means having an oil capacity in excess of thecapacity of the metering port and provided with an inlet below thepropeller shaft in the lower portion of the gear case aforesaid andhaving discharge conduit means leading to said remote means requiringlubrication, said conduit means extending thence to said reservoir,whereby said pump means maintains constant circulation of oil throughsaid submersible gear case and said remote parts requiring lubricationand said reservoir While maintaining the submersible gear casesubstantially free of oil in excess of that required for lubrication ofthe gears therein.

l0. The device of claim 9 in further combination with means forbalancing pressures to which the circulating oil is subject.

References Cited in the file of this patent UNITED STATES PATENTS

